1. Department of Physics, Duke University , Durham, NC 27708, USA
2. Department of Physics, Carnegie Mellon University , 5000 Forbes Ave, Pittsburgh, PA 15213, USA
3. Department of Physics, The Ohio State University , 191 West Woodruff Ave, Columbus, OH 43210, USA
4. Department of Astronomy, The Ohio State University , 140 West 18th Ave, Columbus, OH 43210, USA
5. Department of Physics and Astronomy, University of Pennsylvania , Philadelphia, PA 19104, USA
6. Division of Physics, Math, and Astronomy, California Institute of Technology , 1200 E California Blvd, Pasadena, CA 91125, USA
7. Department of Astrophysical Sciences, Princeton University , 4 Ivy Lane, Princeton, NJ 08540, USA
8. Leinweber Center for Theoretical Physics, Department of Physics, University of Michigan , Ann Arbor, MI 48109, USA
9. SLAC National Accelerator Laboratory , 2575 Sand Hill Road, Menlo Park, CA 94025, USA
10. Division of Physics, Math, and Astronomy, California Institute of Technology , 1200 E. California Boulevard, Pasadena, CA 91125, USA
11. Jet Propulsion Laboratory, California Institute of Technology , 4800 Oak Grove Drive, Pasadena, CA 91109, USA
12. Laboratoire Univers et Particules de Montpellier , Place Eugène Bataillon - CC 72, F-34095 Montpellier Cedex 05, France
13. LPC, Université Clermont Auvergne, CNRS , F-63000 Clermont-Ferrand, France
14. Department of Physics and Astronomy, Rutgers University , Piscataway, NJ 08854, USA
15. Argonne National Laboratory , 9700 S Cass Ave, Lemont, IL 60439, USA
16. University of Texas , Dallas, 800 W Campbell Rd, Richardson, TX 75080, USA
17. Department of Physics and Astronomy, University of Utah , 115 South 1400 East, Salt Lake City, UT 84112-0830, USA
18. Department of Physics and Astronomy, University of Pittsburgh , 4200 Fifth Ave, Pittsburgh, PA 15260, USA